Range support off-by-one error

[fasterthanlime]

When the request header Range is set to bytes=0-, the last byte is missing from the response.

Reproduction steps

Create ohno.txt with contents:

$ printf "life" > ohno.txt
$ sfz -Z &
$ curl -s http://localhost:5000/ohno.txt; echo
[30/Jul/2020 18:08:59] "GET /ohno.txt" - 200 OK
life
$ curl -s http://localhost:5000/ohno.txt -H "Range: bytes=0-"; echo
[30/Jul/2020 18:09:16] "GET /ohno.txt" - 206 Partial Content
lif

Don't use echo to create ohno.txt, it would put a newline in it. Some text
editors also automatically insert newlines

Additional notes

The HTTP Range header is annoying to implement correctly, I recommend writing a bunch of tests around it!

I think just doing end - start + 1 here would fix it:

sfz/src/server/send.rs

Line 162 in d3c0b05

.take(end - start)

...but it's the end of the day and I'm tired, so.

[luser]

hyper's ByteRangeSpec seems really useful, but the conversion to the Content-Range header using to_satisfiable_range puts the information in a less useful form. Seems like it'd be less error-prone to simply validate that the range is satisfiable, and then pass the ByteRangeSpec down into send_file_with_range?

[fasterthanlime]

Thanks for the fix @weihanglo! ✨